The development of information technology provides increasingly rich and powerful applications and services, and at the same time brings forward increasing demands on the computing capacity and storage capability of processing equipment. Therefore, clustered systems can be employed to store and process an immense amount of information and data and to provide services to the clients with high availability. A clustered system includes a group of computing devices that are linked by hardware and software and thus operate together to provide services as a single system image. Such computing devices are referred to as nodes in the cluster.